They boldly claimed they'd beat Facebook in 100 days and began acquiring any startup that pretended to solve a social problem. Every team got a G+ OKR. In classic Google fashion, they chewed up the one social platform they had, Orkut, and gChat, which was filling the AIM void, also squandered its lead as it was subsumed. They never invested enough in their successful/functional video chat, and instead just had team after team launching new versions of the same damn thing. Looking through GCP and their AI/Vertex/Whatever naming soup, not much has changed.

Wave was very simply modern email. Conceptually, there's nothing more to it. It was a new protocol that effectively filled the same basic needs as email, but left room for first class support for the types of features we've either hacked badly on top of email or still lack today - proper threading, traceable message amendment, rich messaging & multimedia support that's not a MIME hack & an improved security posture.

I think that was maybe a secondary problem with Wave: it was marketed as some new voodoo that ended up smelling like a hammer seeking a nail, when it was really just Email 2.0

I think this might actually be the first time I've understood that intention. Fully in agreement with your earlier comment that it was a total turd of a product - I remember a group of friends all getting access, playing with it for about 30 minutes, and then just coming away thinking what an awful experience it was, never to return. None of us were thinking of it as even vaguely email related, it basically felt like forums but worse. Or messaging but worse.